Modification of wool with solution containing formaldehyde and the reaction product of formaldehyde with a monohydrazide or a dihydrazide



United States Patent 3,326,630 MODIFECATION OF WOOL WITH SOLUTION CON- TAINING FORMALDEHYDE AND THE REAC- TION PRODUCT 0F FORMALDEHYDE WITH A MONOHYDRAZIDE OR A DIHYDRAZIDE Robert L. Holbrook, Franklin Lakes, N.J., assignor to Olin Mathieson Chemical Corporation, a corporation, of Virginia No Drawing. Filed Feb. 5, 1964, Ser. No. 342,808 8 Claims. (Cl. 8-128) This invention relates to the treatment of wool to improve resistance to shrinking and to improve flatness characteristics at high humidity. More particularly it relates to the impregnation of woolen textiles with solutions containing formaldehyde and the products of its reaction with a hydrazide.

The use of hydrazide-formaldehyde reaction products to impart wrinkle resistance to textiles, particularly cellulosic textiles, has been briefly described in US. 2,161,808. The use of polymethylol hydrazides of dibasic acids as antiwrinkling or crease-proofing agents for cellulosic textiles is described in US. Patents 2,904,387 and 2,904,388. These patents describe the preparation of the polymethylol hydrazides of di-basic acids by reaction of formaldehyde and dihydrazides of di basic acids and their application to cellulosic textiles. The antiwrinkling agents of US. Patent 2,904,387 are reaction products of formaldehyde (including convenient sources thereof such as paraformaldehyde) and dihydrazides of the general formula R(CONHNH wherein R is (CH wherein n is O to 5, or mixtures of such dihy-drazides, for example oxalic, malonic, succinic, glutaric, adipic and pimelic. The crease-proofing agents of US. Patent 2,904,358 are reaction products of formaldehyde (including conventional sources thereof such as paraformaldehyde) and dihydrazides of the general formula R(CONHNH wherein R is a saturated chain of 2 to 6- carbon atoms and is interrupted by one or two oxygen or sulfur atoms in the form of ether or thioether linkages, for example diglycolic acid, thiodiglycolic acid and the like, or mixtures of such dihydrazides.

In addition, US. Patent 2,904,390 describes creaseproofing compositions for cellulosic textiles derived from formaldehyde (or convenient sources thereof such as paraformaldehyde) with a hydrazide of a monocarboxylic acid having the formula RCONHNHR wherein R is H or an alkyl or substituted alkyl group and R is H or RC O. The R of the formula and-R of the R group can be the same or different. Preferably, the alkyl group contains from 1 to 8 carbon atoms and the substituted alkyl group is substituted by hydroxyl or sulfhydryl groups. Examples of preferred monohydrazides include diformic hydrazide, acetic hydrazide, diacetic hydrazide, glycolic hydrazide, thioglycolic hydrazide, propionic hydrazide, and gluconic hydrazide.

Particularly advantageous crease-proofing of cellulosic textiles is obtained when any of the monohydrazides or dihydrazides described in the above-described patents are combined with formaldehyde and a tetrahydro-striazone to form polymethylol derivatives as described in US. Patent 3,090,665. Still more advantageous results are obtained when the hydrazides are combined with formaldehyde and certain triazines.

The present invention relates to the application of solutions formed from these hydrazides and formaldehyde, which may also contain reaction products of formaldehyde with triazine and/or triazones, to the treatment of wool to reduce shrinking. Solutions containing this particular combination of ingredients impart shrink resistance to Wool as well as the outstanding adv-antages of a high degree of resistance to creasing (measured-by crease angle as described in the examples), a high retention of tensile strength and tear strength, good handle, unimpaired warmth, low chlorine retention and good flatness characteristics at high humidity. The solutions are particular-ly valuable in the treatment of woolen textile materials such as blankets and suiting.

The solutions used in the process of this invention are aqueous solutions containing formaldehyde and a monohydrazide or dihydrazide reaction product. A triazineformaldehyde reaction product or a triazone-forrnaldehyde reaction product may also 'be included. Suitable pad baths for use in the process of this inventioncontain the following proportions of ingredients:

A B O D (1) Formaldehyde, moles 1-20 1-20 1-20 1-20 (2) Triazoue and/or substituted triazone reaction product with (EH10,

moles"; 0.5-8 0.5-8 (3) Triazines and/or substituted triazine reaction product with 01170,

moles 0.5-8 1 (4) Monohydrazide and/or dihydraaide reaction product with CHrO,

moles 1 1 1 1 (5) Water. percent by weight based on entire composition 70-95 70-95 70-95 70-95 (6) Catalyst, percent by Weight based on entire composition 0.2-5 0. 2-5 0. 2-5 0. 2-5

Other proportions of ingredients can be made to function satisfactorily, but the best results are obtained using the above ratios. It is not exactly known how much of the formaldehyde is reacted with the hydrazide and the triazone or triazine but some excess formaldehyde should 'be present. Theoretically, every hydrogen atom attached to a nitrogen atom is reactable with a formaldehyde molecule to form the methylol group, but actually not all these hydrogen atoms react. Thus a hydrazide group (-CONHNH can theoretically react with 3 molecules of formaldehyde and one mole of the dihydrazides described above can theoretically consume 6 moles of formaldehyde. The triazones can theoretically react with 2 moles of formaldehyde if substituted in the 5-position and three rnoles if unsubstituted. Since not all these hydrogen atoms actually react, as little as one mole of formaldehyde per mole of a monohydrazide provides excess formaldehyde in some cases.

The preferred method of preparing the solutions useful in this invention comprises preparing the formaldehydetriazone or formaldehyde-triazine reaction product in about half the total water, adding the additional required formaldehyde, adjusting the pH to about 8 to 9 by the addition of aqueous alkali, for example, 10% caustic and then adding the hydrazide with additional alkali as necessary to maintain the same pH range. Prior to use, catalyst and softener, for example, a polyethylene emulsion, is added and water to make the final volume.

Alternatively, the method of preparing solutions useful in this invention comprises preparing the hydrazide-formaldehyde reaction product containing excess formaldehyde, preparing the triazineor triazone-formaldehyde reaction product containing excess formaldehyde and blending these two solutions to form a concentrate, then diluting with water and adding catalyst. In this procedure, the hydrazide-formaldehyde reaction product is best prepared by slowly adding the hydrazide to aqueous formaldehyde with stirring and cooling to maintain the temperature below about 40C., e.g. about 10 to 30 C. When a monohydrazide is used, the ratio of the latter to the formaldehyde should be about 1 mole of hydrazide to between about 3 and 10 moles of formaldehyde. The reaction goes smoothly at an alkaline pH. It is preferable vo maintain the pH at about 7 to 10, preferably 7 to 9, luring the formaldehyde-monohydrazide reaction to avoid zhe formation of any resinous product. This can be done :y the incremental addition of a dilute base, e.g., sodium iydroxide. When a dihydrazide is used the mole ratio rhould be about 4 to 20 moles of formaldehyde per mole )f the dihydrazide. Also, when reacting dihydrazide with formaldehyde, care should be taken not to allow the pH to become acid during the addition period to avoid the Formation of solid products. This is easily done by drop- Nise addition of a dilute base such as sodium hydroxide )r sodium carbonate. Very little is required. The pH is naintained at about 6 to 11, preferably about 7.5 to 9.5. lhe water present should come to about 40 percent to 30 percent by weight of the final composition.

The tetrahydro-s-triazones useful in this invention for forming polymethylol substituted triazones are those of the formula:

wherein R and R are each independently selected from the group consisting of hydrogen, alkyl radicals of 1 to :arbon atoms and hydroxyalkyl radicals of 1 to 5 carbon atoms. Tetrahydro-s-triazone OC(NHCH NH, tetrahydro-S-ethyl-s-triazone OC'(NHCH NC H and tet- ."ahydro-5-beta-hydroXyethyl-s-triazone OC (NHCH NCH CH OH are especially useful.

Triazines suitable for use in this invention include melamine particularly, guanamine and partially substituted melamines and guanamines of the forumla:

where R, is selected from the group consisting of hydrogen, alkyl of 1 to 5 carbon atoms, aryl NHR and NHR and where R and R are each selected independently from the group consisting of hydrogen, alkyl of 1 to 5 carbon atoms and aryl.

These triazines react with formaldehyde (aqueous formaldehyde or paraformaldehyde) in an aqueous mixture to form polymethylol derivatives having 2 to 6 methylol groups. The latter groups may be etherified by adding a lower alkanol to the mixture during or after the reaction with formaldehyde.

The triazone or triazine-formaldehyde reaction products can be prepared in several ways but it is preferable to prepare the triazone or substituted triazone from urea and ammonia or an amine in the presence of aqueous formaldehyde. Better results are obtained than when the preformed triazone is reacted with aqueous formaldehyde with or without the presence of a hydrazide. Accordingly, equimolar quantities of urea and either ammonia and/ or an amine are dissolved in water. If ammonia is used, the product is unsubstituted triazone, but if an amine is used the substituent thereon will appear in the triazone, at the 5-position:

RNH 2CH O CO (NI-I CO (NHCH NR+2H O Next the formaldehyde, preferably paraformaldehyde, is slowly added while agitating and cooling the mixture to maintain its temperature below about 70 C. After all of the formaldehyde is added, the solution is refluxed at 90 to 100 C. for about to 1 /2 hours and then is allowed to cool to room temperature. It is then ready to be mixed with the hydrazide solution and diluted for use.

d The proportions of ingredients selected in the above preparation are:

Urea moles 1 Ammonia or amine do 1 Formaldehyde do 4-10 Water percent by weight" 15-50 After the polymethylol hydrazide and polymethylol triazone solutions are prepared they are mixed to form a concentrate or they can be mixed and diluted or diluted and mixed to form the pad bath containing percent to percent by weight of water. An alternative method for preparing the concentrate comprises reacting the hydrazide and formaldehyde by mixing the hydrazide with a solution containing the triazineor triazone-formaldehyde reaction product and enough excess formaldehyde to form the concentrate described above. If desired, a water soluble alcohol, methanol preferred, can be added to the concentrate up to 50 percent by weight to stabilize it against precipitation of solids during prolonged storage.

The addition of certain catalysts to the polymethylol solution is desirable before use in treating wool in order to make the treatment more durable to laundering. Suitable catalysts include magnesium chloride, magnesium nitrate, zinc chloride, zinc nitrate, aluminum sulfate, p-toluene sulfonic acid and its ammonium salt, maleic acid, citric acid and mixtures thereof. The catalyst is added to the extent that the pad bath contains 0.2 percent to 5.0 percent by weight of solid catalyst based on the weight of the pad bath. The catalyzed solution is then ready to be applied to the wool.

In accordance with the invention, a solution or diluted concentrate prepared as described above is padded onto the cloth, while the padding bath has :a pH from about 2 to about 7 and preferably about 5.5, to the extent that the dry pick-up or add-on, after the cloth is cured, is between about 2 percent and 15 percent by weight, based on the weight of the dry cloth. This add-on is generally accomplished by a wet pick-up of about 65 to about percent or even somewhat more with the baths described above.

The curing step, i.e., the reaction of the formaldehyde adduct with the wool is carried out by heating the wet textile until dry and then further heating to eifect the curing. Complete cure can be obtained by heating at 280 to 350 F. for 0.5 to 20 minutes. The curing period is temperature dependent and can be varied over a wide range. Thus, complete curing can also be attained in 15 to 60 seconds at tempeatures above 200 C. The drying and curing can be combined in a single operation for example, at 300 F. for 20 minutes. After the cloth has been cured, it is finished according to standard woolen mill procedure.

Example I A solution was made up having the following proportions of ingredients:

Weight percent Diglycolic dihydrazide 4.1 Aerotex 23 (polymethylol melamine, 50 percent active) 6.5 Formaldehyde (37 percent) 4.6 Polyethylene softener 2.5 Zinc nitrate (31 percent) 3.0 Water 79.3

The solution was padded onto a wool blanket to a pickup of 100 percent equal to 12 percent total resin on a dry basis. The blanket was dried and cured by heating at 150 C. (300 F.) for 10 minutes. Shrinkage was determined by Federal Specification CCC-T-191a Wash Test Method. The following results were obtained:

Untreated Product of Example I Test Warp Fill Warp Fill Shrinkage (1 wash), pct 6. 9 10. 0.9 2. 1 Tensile strength 33 46 28 27 Anticrease (232) (252) Example II The pad solution of Example I was applied to wool suiting. Pickup was 100 percent and cure conditions were the same as in Example I. The results follow:

Untreated Product of Example 11 Test Warp Fill Warp Fill Shrinkage (1 wash), pct 18. 8 7. 2 1. 3 1.3 Tensile strength 16 19 14 Anticrease (297) (310) The marked decrease in shrinkage was achieved without significant loss of tensile strength. In addition a very desirable increase in anticrease was obtained which contributes resistance to mussing. Also the handle of the resinated fabric was not significantly affected. The flatness characteristics at high humidity were good.

What is claimed is:

1. Method for the treatment of wool to render it resistant to shrinking which consists of the steps of wetting the Wool with an aqueous solution of the ingredients (1) formaldehyde and (2) a formaldehyde-hydrazide reaction product selected from the group consisting of (a) the reaction product of formaldehyde and a monohydrazide of the formula RCONHNHR' wherein R is selected from the group consisting of hydrogen, alkyl of 1 to 8 carbon atoms and alkyl of 1 to 8 carbon atoms substituted by one of the groups hydroxyl and sulfhydryl and R is selected from the group consisting of hydrogen and RC=O, the molar ratio of formaldehyde to said monohydrazide being from 3:1 to 10:1, and (b) the reaction product of formaldehyde and a dihydrazide of the formula R(CONHNH wherein R is selected from the group consisting of 2)n wherein n is an integer from 0 to 5 and alkylene of 2 to 6 carbon atoms interrupted by from 1 to 2 atoms selected from the group consisting of oxygen and sulfur, the molar ratio of formaldehyde to said dihydrazide being from 4:1 to 20:1; the total amount of said ingredients in said solution being at least 5 Weight percent and the proportions of formaldehyde in said solution being from 1 to 20 moles per mole of said formaldehyde-hydrazide reaction product; and heating the thus wetted wool at 280 to 350 F.

for 0.5 to 30 minutes to render the wool resistant to shrinking.

2. Method for the treatment of wool to render it resistant to shrinking which consists of the steps of wetting the wool with an aqueous solution of the ingredients (1) formaldehyde and (2) the reaction product of formaldehyde and diglycolic dihydrazide, the molar ratio of formaldehyde to said dihydrazide being from 4:1 to 20:1; the total amount of said ingredients in said solution being at least 5 weight percent and the proportion of formaldehyde in said solution being from 1 to 20 moles of formaldehyde per mole of said formaldehyde-hydrazide reaction product; and heating the thus wetted wool at 280 to 350 F. for 0.5 to 30 minutes to render the wool resistant to shrinking.

3. Method for the treatment of wool to render it resistant to shrinking which consists of the steps of wetting the wool with an aqueous solution of the ingredients (1) formaldehyde and (2) the reaction product of formaldehyde and acetic hydrazide, the molar ratio of formaldehyde to said hydrazide being from 3:1 to 10:1; the total amount of said ingredients in said solution being at least 5 weight percent and the proportions of formaldehyde in said solution being from 1 to 10 moles of formaldehyde per mole of said formaldehyde-hydrazide reaction product; and heating the thus wetted textile at 280 to 350 F, for 0.5 to 30 minutes to render the wool resistant to shrinking.

4. Method of claim 1 in which a formaldehyde reaction produce of a triazone of the formula wherein R and R are independently selected from the group consisting of hydrogen, alkyl of 1 to 5 carbon atoms and hydroxyalkyl of 1 to 5 carbon atoms is added to said aqueous solution in a proportion of 0.5 to 8 moles per mole of formaldehyde-hydrazide reaction product.

5. Method of claim 1 in which a formaldehyde reaction product of a triazine of the formula wherein R is selected from the group consisting of hydrogen, alkyl of 1 to 5 carbon atoms, aryl, NHR and NHR and R and R are each selected independently from the group consisting of hydrogen, alkyl of 1 to 5 carbon atoms and aryl is added to said aqueous solution in a proportion of 0.5 to 8 moles per mole of formaldehyde-hydrazide reaction product.

6. Method of claim 5 in which said triazine is melamine.

7. Method of claim 1 in which 0.2 to 5 weight percent of a catalyst selected from the group consisting of ma ncsium chloride, magnesium nitrate, zinc chloride, Zinc nitrate, aluminum sulfate, p-toluene sulfonic acid and its ammonium salt, maleic acid, citric acid and mixtures thereof is added to said solution.

8. W001 which has been rendered resistant to shrinking by the method of claim 1.

References Cited UNITED STATES PATENTS 2,161,808 6/1939 Finlayson et al. 8-1l6.3 X 2,845,400 7/1958 Rudner 8-1163 X 2,904,387 9/1959 Holbrook et al 8116 .3 2,904,388 9/1959 Holbrook et al. 8116.3 2,904,389 9/1959 Thomas et al. 8--116.3 2,904,390 9/1959 Doerr et al 8116.3 3,090,665 5/1963 Parsons et al. 8116.3

NORMAN G. TORCHIN, Primary Examiner.

J. CANNON, Assistant Examiner. 

1. METHOD FOR THE TREATMENT OF WOOL TO RENDER IT RESISTANT TO SHRINKING WHICH CONSISTS OF THE STEPS OF WETTING THE WOOL WITH AN AQUEOUS SOLUTION OF THE INGREDIENTS (1) FORMALDEHYDE AND (2) A FOREMALDEHYDE-HYDRAZIDE REACTION PRODUCT SELECTED FROM THE GROUP CONSISTING OF (A) THE REACTION PRODUCT OF FORMALDEHYDE AND A MONOHYDRAZIDE OF THE FORMULA RCONHNHR'' WHEREIN R IS SELECTED FROM THE GROUP CONSISTING OF HYDROGEN, ALKYL OF 1 TO 8 CARBON ATOMS AND ALKYL OF 1 TO 8 CARBON ATOMS SUBSTITUTED BY ONE OF THE GROUPS HYDROXYL AND SULFHYDRYL AND R'' IS SELECTED FROM THE GROUP CONSISTING OF HYDROGEN AND RC=O, THE MOLAR RATIO OF FORMALDEHYDE TO SAID MONOHYDRAZIDE BEING FROM 3:1 TO 10:1, AND (B) THE REACTION PRODUCT OF FORMALDEHYDE AND A DIHYDRAZIDE OF THE FORMULA 